emerald ash borer

The emerald ash borer is spreading westward again in Michigan. One of the insects was discovered in a trap set by the U.S. Department of Agriculture. The USDA placed 122 traps in Upper Peninsula counties that had not yet been invaded by the ash borer.

The emerald ash borer is said to be the most destructive, most costly bug that has ever attacked trees in North America.

It is responsible for wiping out untold millions of ash trees from New Jersey all the way to Colorado.

And it all started in a southeast Michigan town: Canton.

Dan Herms is a professor of entomology at Ohio State University. Herms says the emerald ash borer almost certainly arrived via infested wood used in international commerce, like solid wood packing built from infested ash trees in Asia.

Herms added the emerald ash borer is especially devastating because it feeds on the vascular tissue of the tree, which is the tissue that moves water and nutrients between roots and the leaves.

According to an article which Herms co-authored, emerald ash borers are the most costly biological invasion by an exotic forest insect to date.

“In Ohio only, research estimated that the insect will ultimately cost $4 to $7 billion, including the death and replacement of ash trees in the urban environment,” says Herms.

The emerald ash borer is a little shiny green beetle that loves to feast on ash trees. The adult beetles only nibble on the leaves. It's the larvae you've got to watch out for. They munch on the inner bark of the ash tree, and mess with the tree's ability to transport water and nutrients.

The pest has killed tens of millions of ash trees in Michigan alone and tens of millions more in the states and provinces around our region.

Now researchers know a little bit more about how the emerald ash borer ate its way through the state.

Researchers are uncovering evidence for a timeline for the arrival of an invasive beetle that has destroyed tens of millions of ash trees in the U.S. and Canada.

The emerald ash borer is native to China. Scientists think it arrived in the U.S. via wood packing crates. The beetle eats through the living part of an ash tree underneath the bark and cuts off the tree's water and food supply. This starves the tree to death.

The ash borer continues to spread across the U.S. The researchers found that it may have arrived in North America a decade before it first was detected.

More from the Associated Press:

Michigan State University researchers collected cores from trunks of more than 1,000 ash trees in six southeastern Michigan counties. By studying them, they determined the year each tree was killed by the emerald ash borer and found trees killed as early as 1997.

The ash borer was detected in southeast Michigan in 2002. The researchers say it would take several years before the beetle population was large enough to kill trees, so they concluded it had been in southeast Michigan since at least 1992 or 1993.

Red-bellied woodpeckers and white-breasted nuthatches, to be specific.

Scientists say the two bird species thrived when the emerald ash borer moved in. The invasive insect wiped out tens of millions of ash trees around the region.

The researchers compared four bird populations in the outbreak’s epicenter in southeastern Michigan (near the Detroit Metro Airport), to the populations outside just of the epicenter and with five other cities in the region (Cincinnati, Cleveland, Columbus, Indianapolis, and Pittsburgh).

Both problems continue to spread, but many forests still have healthy trees in them.

Foresters from the Michigan Department of Natural Resources and Michigan Tech are taking a closer look at more than 30,000 acres of state forest land.

Andrew Storer, professor of forest and insect ecology at Michigan Tech, said the plan is to harvest healthy stands of ash and beech trees before they’re affected.

"If it's consistent with the management objective of the stand, then removing resources that you know are not going to persist until the next cutting cycle makes a lot of sense just in terms of getting the value out of those trees while they’re still in the forest," said Storer.

Storer said harvesting these trees now can also help forest ecology.

"It helps the forest by getting a head start, if you like, on what the future forest is going to be, and so by removing trees now and getting the value from that, we’ll start to see what the regenerating forest is going to be, and through management be able to direct that regeneration toward species that are going to be successful in the forest in the future," said Storer.

In a press release, the Michigan DNR said the goal is not to remove all beech or ash trees in these forests, but to thin them to a healthier level.

"We are using criteria including proximity to the nearest infested site, infestation, size, density and quality of trees, and accessibility, in order to prioritize which areas need attention," said Bill O'Neill, chief of the DNR's Forest Resources Division, who also serves as state forester. "Considering other factors important to maintaining healthy forests, harvests are being scheduled to remove the beech and ash and regenerate the stand to a desired, productive species mix. The goal is not to remove all beech or ash, but to reduce them to a level that the mortality will not significantly impact the quality of the remaining trees or the productivity of the forest."

Researchers started surveying state forest land for this project last June and plan to continue surveying through next summer.

There’s so much to know about what’s happening in the world around us, and that information gives us insights into patterns and changes that could have a big impact on our lives.

But finding these trends requires a lot of data – and somebody has to go out and get it.

Chris Kort is one of those people. He's an ecological surveyor counting trees in Detroit. For every tree he counts, Kort marks where the tree is, then he adds details like its size, species, and health.

Kort does this all day long, walking up and down Detroit streets, counting trees on city property.

“Since March, I have surveyed 13,468 trees. And counting,” he says.

The data from this survey will go to the city, the state, and scientists at the U.S. Forest Service. It will tell a story about what’s happening to trees in the city.

A database like this has to be built manually by people like Chris Kort, tree by tree.

Kort is like the human version of the Google street view car, roving up and down blocks and adding to his map. He notices details that most people miss. There are some things you can only find on foot.

“I’ve actually been collecting pennies on the sides of the roads for, like four months," says Kort, "I cashed in 2,200 pennies yesterday. People just don’t pick them up anymore apparently.”

An invasive insect may wipe out the ash trees at Sleeping Bear Dunes National Lakeshore. The emerald ash borer has infested up to 90 percent of the ash trees on the lakeshore's mainland in the northwestern Lower Peninsula. The first case was discovered in June and the tree-killing pest has spread quickly.

Lakeshore officials are considering their options to try to control the ash borer, but things look bleak.

The emerald ash borer is native to eastern Russia, northern China, Japan, and Korea. It turned up in Michigan in June of 2002, most likely from wood used in packing materials in international cargo ships.

Since its arrival, the bug has led to the death of tens of millions of ash trees.

Removing these trees can be expensive and while some cities have seen the financial bite come and go, others are still feeling it.

Eric Dresden writes in the Saginaw News that the city is unsure how it will pay for the removal of hundreds of dead ash trees. From the Saginaw News:

Of the 6,000 ash trees lining the city’s streets, Simeon Martin expects thousands could be dead by the end of this year.

The cause: an emerald ash borer infestation brewing for at least nine years.

“When spring comes out, that will be the tell-tale time,” said Martin, chief foreman of the city’s streets division.

Last year, the city found 400 dead trees, and this year could be a lot worse, he said. Those trees were removed, and the city is continuing to take down infested ashes, Martin said. This year, he said, the infestation is expected to grow faster than crews can take down the trees.

Dresden reports the city has no money set aside for the removal of dead and dying trees, and when the trees are removed, no new trees are being planted because the city doesn't have the budget to maintain them.

...people continue to make the invasive species problem worse by moving firewood infested with exotic organisms. The unwelcome critters also work their way into nursery stock and wooden pallets that are hauled around the state.

Lynne Boyd is chief of the Forest Management Division and says insects and foreign species are a big danger to Michigan's 19.3 million acres of woodlands. Industries connected to Michigan forests such as timber and recreation provide 136,000 jobs and pump $14 billion into the state's economy each year.

The Michigan Department of Agriculture has set up a quarantine to limit the ash borer's spread — including a firewood checkpoint at the Mackinac Bridge linking the Upper Peninsula and Lower Peninsula. People caught hauling firewood into the U.P. can be fined or even jailed. Even so, the ash borer has been found in several U.P. locations after killing more than 30 million ash trees in southeastern Michigan.